Brian Dunbar
Headquarters, Washington, D.C.
August 20, 1992
(Phone: 202/358-0873)
Keith Koehler
Wallops Flight Facility, Wallops Island, Va.
(Phone: 804/824-1579)
RELEASE: 92-135
NASA STUDYING PACIFIC OCEAN PLANT PRODUCTIVITY
NASA researchers will begin a 3-week airborne study on Aug.
20 to increase understanding of microscopic plant productivity
in the equatorial region of the Pacific Ocean.
Dr. Frank Hoge, principal investigator from Goddard Space
Flight Center's Wallops Flight Facility, Wallops Island, Va.,
said the principal scientific objective is to understand why
microscopic plant productivity is so limited in the Pacific
compared to the Atlantic Ocean.
Microscopic plants, called phytoplankton, are an important
part of the marine food chain as nutrition for small animals and
fish. Phytoplankton also plays an important role in the
absorption of carbon dioxide from the atmosphere. Carbon
dioxide is a "greenhouse gas" that traps heat near the Earth's
surface. Increasing concentrations of carbon dioxide in the
last 100 years, primarily through humans' use of fossil fuel,
has led to concerns that human activity may be increasing the
Earth's temperature.
Hoge points out that the Pacific Ocean equatorial region has
amounts of nutrient concentrations, sunlight and phytoplankton
seed similar to those found in the Atlantic Ocean. However,
phytoplankton in the Atlantic is more abundant than in the
Pacific, he said.
The NASA-Wallops researchers will conduct their study during
four flights at 500 feet (152 meters) altitude, slightly less
than the height of the Washington Monument, using the Airborne
Oceanographic Lidar (AOL) and other instruments aboard Wallops'
P-3B aircraft. The flights are expected to last about 12 hours
each.
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The Wallops instruments on the aircraft allow researchers to
survey large stretches of the Pacific Ocean. Hoge said the
researchers will use active and passive data-collection
techniques to help them develop analytical tools for future
satellites that will map phytoplankton concentrations on a
world-wide scale.
In addition to measuring the phytoplankton, the researchers
also will measure dissolved organic matter in the ocean. Hoge
said the organic matter interferes with gathering accurate
satellite phytoplankton measurements.
The AOL transmits a green light pulse from a laser into the
water where the light is absorbed by the phytoplankton. A
receiver on the aircraft detects the green light reflected from
the water surface and red light which is emitted by chlorophyll
pigment in the phytoplankton.
At the same time, another instrument on the aircraft is
taking measurements from sunlight reflected from the water and
light emitted by the chlorophyll. Satellites, which lack the
facilities to power a laser system, measure changes in ocean
color that indicate where concentrations of phytoplankton are
located.
Wallops researchers will base their flights from Hilo,
Hawaii. They will fly to 140 degrees west longitude and 5
degrees north of the equator. Measurements will be taken in
conjunction with the University of Washington scientific
research vessel "Thomas G. Thompson."
Once the P-3 aircraft reaches 3 degrees south of the equator,
the P-3 will turn toward the west taking measurements on both
sides of the equator as the plane advances towards Christmas
Island.
The NASA project is part of the Joint Global Ocean Flux Study
supported by the National Science Foundation, Washington, D.C.
The project is managed by Wallops for NASA's Office of Space
Science and Applications, Washington, D.C.
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